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Feed provided by Analytical and Bioanalytical Chemistry Research. Click to visit.Recent Advances in Microextraction Methods for Sampling and Analysis of Volatile Organic ...http://www.analchemres.org/article_82462_8603.html
Human exposures to volatile organic compounds (VOCs) are associated with a wide range of health problems. Due to these adverse effects of VOCs on the human health, determination of trace levels of VOCs is very important for accurate assessment of indoor and outdoor exposure. Solid phase microextraction (SPME), needle trap device (NTD) and hollow fiber- liquid phase microextraction (HF-LPME) are increasingly used for accurate determination of VOCs in air. In this paper, authors have reviewed new developed forms of SPME, NTD and LPME techniques for the sampling and analysis of VOCs in air with a main focus on SPME coating fibers and NTD sorbents. The effects of some environmental and device parameters on SPME and NTD samplers are also reviewed. Moreover, several analytical parameters such as carryover effect, storage time, limit of detection (LOD) and limit of quantitation (LOQ) of these new technologies are discussed. Finally, the applicability, limitations and future trends of these methods are reviewed.Sat, 30 Nov 2019 20:30:00 +0100Statistical Optimization of Removal of Safranin Dye from Aqueous System Using Biosorbent ...http://www.analchemres.org/article_82493_8603.html
The biosorption performance of Phlomis cancellata Bunge as inexpensive, abundant and easily available adsorbent for safranin cationic dye removal from aqueous system has been evaluated in a batch process, using response surface methodology and employing a central composite design Experimental. The influence of different parameters such as, pH, contact time, agitation rate and sorbent dosage on the removal of safranin was examined. The significance of independent variables and their interactions were tested by analysis of variance (ANOVA). The optimum contact time, pH, agitation speed and adsorbent dose were found to be 39.96 min, 9.0, 331.18 rpm and 20mg/mL, respectively. Under these conditions, the maximum sorption capacity for safranin was found to be 99.60%. The kinetics of dye sorption fitted well with pseudo-first order kinetic model. The isotherm data of safranin could be well described by Langmuir model (R2 = 0.9924). The method was successfully applied for the removal of safranin from industrial wastewater and groundwater samples.Sat, 30 Nov 2019 20:30:00 +0100Dispersive Liquid-Liquid Microextraction Based on Solidification of Floating Organic Drop as an ...http://www.analchemres.org/article_82494_8603.html
A rapid, simple, and sensitive dispersive liquid-liquid microextraction based on solidification of floating organic drop (DLLME-SFOD) method coupled with UV&ndash;Vis spectrophotometry has been applied for the extraction and determination of trace amounts of aluminium. The aluminium was extracted from the aqueous media containing aluminon and cetyltrimethylammonium bromide (CTAB). After rapid injection of the mixture of 1-undecanol as the extraction solvent and ethanol as the disperser solvent into the sample, a cloudy mixture was formed and the complex was extracted into 1-undecanol. After centrifugation and cooling in an ice bath, the solidified organic drop on top of the solution was transferred into a vial which was melted at room temperature. Then, the organic phase containing the metal complex was diluted with ethanol and was transferred into a microcell for quantification. The pink chelate exhibits maximum absorbance at 535.0 nm, and with a preconcentration factor of 100.0 obeys Beer&rsquo;s law over the concentration range of 1.0-15.0 &micro;g L-1 of aluminium. The limit of detection of 0.14 &mu;g L-1 and a relative standard deviation of 1.8% at 3.0 &mu;g L-1 (n = 6) were obtained. The procedure was successfully applied for the determination of aluminium in tea and water samples.Sat, 30 Nov 2019 20:30:00 +01003D-QSAR Modeling of Anti-oxidant Activity of some Flavonoidshttp://www.analchemres.org/article_82495_8603.html
The anti-oxidant activities for a diverse set of flavonoids as TEAC (Trolox equivalent anti-oxidant capacity), assay were subjected to 3D-QSAR (3 dimensional quantitative structural-activity relationship) studies using CoMFA (comparative molecular field analysis) and CoMSIA (comparative molecular similarity indices analysis). The obtained results indicated superiority of CoMSIA model over CoMFA model. The best CoMSIA model is developed by using hydrogen-bond donor (H-bond donor) and electrostatic field components. This model gave the cross-validated correlation coefficient, Q2 = 0.512, correlation coefficient, R2 = 0.950, standard error of prediction, SE = 0.284, and F = 47.3, for training set, R2 = 0.922 and SE = 0.286, for test set indicating robustness and high prediction power of the developed model. The contour maps of electrostatic and H-bond donor fields of CoMSIA model provide interpretable and fruitful relationship between chemicals structure and their anti-oxidant activities, which give useful insights for designing new compounds with higher activity.Sat, 30 Nov 2019 20:30:00 +0100Fluorescence Chemosensing of Mg2+ by Phenylhydrazone of a Difluorenylpiperidin-4-onehttp://www.analchemres.org/article_82633_8603.html
Magnesium is an abundant element in the environment. Magnesium ion sensing by fluorescence spectral method is of importance due to the need for the detection of the metal in the human body and the environment. In this paper, we report the Mg2+ ion sensing behavior of the phenylhydrazone derivative of a difluorenylpiperidin-4-one. The preparation method of this compound is simple. The compound shows an enhanced absorption and fluorescence in the presence of Mg2+ ions, strikingly different from the other metal ions, which do not show significant spectral changes. The stoichiometry and the binding strength of the Mg2+ complex of the phenylhydrazone are determined. The compound shows an association constant of 3375.36 M-1 on binding to Mg2+. The range of detection and the competitive binding behavior of Mg2+ are reported. The phenylhydrazone of the difluorenylpiperidin-4-one shows appreciable selectivity and sensitivity of detection for Mg2+ ions. The compound shows promising result in determination of Mg2+ ions in water sample.Sat, 30 Nov 2019 20:30:00 +0100